The present invention relates to a ring binder mechanism which is secured to a base member, such as a cardboard cover, to form a storage device of the note-book type for storing loose-leaf pages, such as the commonly known three-ring binder.
Conventional ring binder mechanisms are generally constructed of a substantially rigid elongated upper member or housing supporting a pair of plates mounted for pivotal movement within the housing with each plate carrying a plurality of half-rings, commonly three. Each half-ring on one plate is aligned with a similar half-ring on the other plate so that in a closed position the half-rings form a closure, generally circular or D-shaped in configuration, for holding a plurality of loose-leaf pages within a binder or base member to which the binder mechanism is secured. Commonly, the half-rings in conventional ring binders extend up through openings or slots formed in the binder upper member or housing such that loose-leaf pages mounted to the half rings through holes adjacent the pages"" edges rest on the upper surface of the housing, as is shown for example in U.S. Pat. No. 5,971,649. In addition, some conventional ring binder mechanisms have their half-rings mounted so as to extend around the lateral edges of the housing and outward a sufficient distance that the loose-leaf pages rest on a relatively horizontal portion of the half-rings such that the edges of the paper do not touch the housing, as is shown for example in U.S. Pat. Nos. 3,263,687 and 4,552,478. It is also common to use such ring binder mechanisms either attached to the spine of the cover or base member or attached to one side of the cover or base member. Because of the shape of the half-rings and their manner of fastening to and positioning on the binder mechanism in these conventional ring binder mechanisms, the overall dimensions of the cover or base member which must surround them and the loose-leaf pages must be large enough to accommodate these structures as well as provide sufficient clearance between the bottom of the ring binder mechanism and the cover or base to allow the half-rings to be moved to their open position where pages can be inserted. It is desirable to reduce the size of the base member or cover while maximizing and/or maintaining its capacity to hold loose-leaf pages. The present invention is directed to such an endeavor.
The present invention provides a ring binder mechanism which allows for the reduction in the size of the base member or cover of a binder while maintaining and/or increasing the capacity of the binder for loose-leaf pages. This is achieved by providing a ring binder mechanism adapted to be secured to a base member, comprising a substantially rigid upper member supporting a pair of pivotable lower members to which a plurality of pairs of respective half-ring members are secured and wherein the pivotable members are pivotably movable between a first position in which the pairs of half-ring members are closed and a second position in which the pairs of half-ring members are open and wherein at least one of the half-ring members of each pair has a lower portion adjacent the upper member substantially in abutment with a lateral edge of the upper member when the pairs of half-ring members are in the first position. In addition, the ring binder mechanism preferably further includes the lateral edge of the upper member being straight along substantially the entire length of the upper member. It also preferably includes the at least one of the half-ring members of each pair extends around the lateral edge of the upper member and beneath one of the pair of pivotal members and the at least one of the half-ring members of each pair being secured to a bottom surface of the one of the pair of pivotal members.